γ. Sulphuric acid leaves the γ. Sulphuric acid dissolves it scaly crystals at first un- with a red colour; Fröhde’s coloured, then slowly develops a reagent[334] a beautiful cherry- reddening. It does not blister. red; tannic acid precipitates a Warm alcoholic potash-lye colours yellowish-white. _Colocynthin._ it a transitory red. _Santonin._ δ. Sulphuric acid colours the δ. Sulphuric acid colours it crystals almost black, whilst it gradually a beautiful red, whilst takes itself a beautiful red tannin does not precipitate. colour. _Cubebin._ _Constituents of the Pimento._ B. CRYSTALS PALE TO CLEAR YELLOW. B. PURE YELLOW RESIDUE. α. _Piperin._ α. Sulphuric acid dissolves it yellow; on the addition of nitric acid, this solution is green, quickly changing to blue and violet. _Colchicine._ β. _Picric Acid._ β. Sulphuric acid dissolves with separation of a violet powder; caustic potash colours it red; sulphide of ammonia violet, and, by heating, indigo-blue. _Chrysammic acid._ γ. Caustic potash dissolves it purple. _Aloetin._ C. MOSTLY UNDEFINED COLOURLESS C. A GREENISH BITTER RESIDUE, CRYSTALS. which dissolves brown in concen- trated sulphuric acid; in Fröhde’s reagent, likewise, at first brown, then at the edge green, changing into blue-violet, and lastly violet. _Constituents of wormwood, with absynthin, besides quassiin, menyanthin, ericolin, daphnin, cnicin, and others._ α. Sulphuric acid dissolves it green-brown; bromine colours this solution red; dilution with water again green. The substance renders the heart-action of a frog slower. _Digitalin._ β. Sulphuric acid dissolves it orange, then brown, lastly red- violet. Nitric acid dissolves it yellow, and water separates as a jelly out of the latter solution. Sulphuric acid and bromine do not colour it red. _Gratiolin._ γ. Sulphuric acid dissolves it red-brown. Bromine produces in this solution red-violet stripes. It does not act on frogs. _Cascarillin._